I have a bad information for you. With almost 100% sure, you bricked your device and there is no possibility how to unbrick it back. Please check the thread below, my colleague described there the situation which had happened to you.

I've killed an MPC5748G (on my own board) by turning off power during programming (oops), and had to swap the BGA chip to recover, as even an external programmer had trouble connecting. So I think it's unrecoverable AFAIK if the reset line is not toggling. Note in some cases i had to do a careful power-cycling/connect with debugger timing to escape a reset escalation. If you haven't fully bricked the device it may need some experimentation to escape the reset escalation?

If you are ordering dev-boards get a few of them - if they are $40 it's cheaper than the chip itself in qty 1 anyway. The root cause (mentioned in other thread) is that the chip (by design) sees the corrupt data as a possible attack perhaps, so just locks itself out.

Thanks for the clarification! The PEMicro pops up a "device may have entered reset escalation, power cycle board" message sometimes. Is there something I need to enable to automatically solve this?

I had mentioned this to Clement as I was getting the same error message in both cases it seemed (the one where it was recoverable, and the one where it isn't). It's worth nothing I have a very oddball hardware design as it's part of a security validation suite, so there is some differences w.r.t. the power supply on the board that can probably cause reliability issues.

I forgot to mention this point. S32DS sometimes shows this pop up windows, but it is often false positive. It means that microcontroller is not in reset escalation, but S32DS debugger warns you, that it could be in reset escalation state. This probably caused by that reset line is in 0 (in reset escalation is reset line 0 after some toggling), but in the second case, reset line is always 0 (without toggling).

Thank you guys ! I did check at the oscilloscope. You spoke about the reset line (here and there DEVKIT-MPC5748G is in reset state). I choose to scrutinize the MCU-RSTX pin, but I don't know if it is the right one...

Nevertheless, this pin is perfectly alive on the remaining functional board but is desperately flat and null on the broken one

If I didn't mistake, I have a brick !

Is this issue a design problem of the board or the CPU ? Could we hope to solve this with a better design of a custom PCB, or is it a feature/bug of the micro itself ?

this is neither design problem nor CPU problem, but this is chip security feature. As Colin wrote above: The root cause (mentioned in other thread) is that the chip (by design) sees the corrupt data as a possible attack perhaps, so just locks itself out.

We have already reported this to S32DS team and in new S32DS release, there should be "fix" which ensures, that HSM blocks will not be included to memory mass erase.

Initializing.MPC574xC Device detected. Target has been RESET and is active.CMD>CM C:\NXP\S32DS_Power_v2017.R1\eclipse\plugins\com.pemicro.debug.gdbjtag.ppc_1.7.2.201709281658\win32\gdi\P&E\nxp_mpc5748g_1x32x1520k_cflash.pcp